Debt Obligations - Schedule of Debt Obligations (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Debt Obligations
Deferred mortgage costs	$ (6,452)	$ (6,646)
Total debt obligations, net of deferred costs	845,777	808,860
Mortgages payable
Debt Obligations
Total debt obligations, net of deferred costs	814,829	778,106
Deferred mortgage costs	(6,100)	(6,289)
Junior subordinated notes
Debt Obligations
Total debt obligations, net of deferred costs	37,400	37,400
Deferred mortgage costs	$ (352)	$ (357)